Project Summary: Barrett's esophagus (BE) is a metaplastic change of the lining of the esophagus, with the normal squamous epithelium replaced by specialized columnar epithelium. The significance of BE lies in its malignant potential subjects with BE have a risk of developing adenocarcinoma of the esophagus that is 30-120 times that of the general public. It is estimated that 10% of those with chronic heartburn harbor BE, and approximately 25% of subjects with BE are women. To date, our understanding of how risk factors for BE differ between women and men is limited because the few studies including women are single center reports featuring small numbers of patients. Our long-term goal is to understand the risk factors for BE in women and men. The specific aims of this secondary data analysis are: 1) To evaluate the association between BMI and Barrett's esophagus in women and compared to men, 2) To evaluate the association between body fat distribution and Barrett's esophagus in women and compared to men, and, 3) To evaluate the association between smoking status and Barrett's esophagus in women and compared to men. Our research plan is to perform a case-control study by combining data from five sites participating in the new NIH consortium, the Barrett's Esophagus and Esophageal Adenocarcinoma Consortium (BEACON). Participating sites will include: Kaiser Permanente, Northern California, the Fred Hutchinson Cancer Institute, the University of North Carolina, the Northern Irish Factors Influencing Barrett's/Adenocarcinoma Relationship (FINBAR) study group, and the Australian Barrett's Esophagus and Esophageal Adenocarcinoma study group. Collectively, these studies contain approximately 1,309 cases of Barrett's esophagus with approximately 327 women, 1551 GERD controls (approximately 388 women) and 1359 population controls (approximately 340 women) Cases will be women and men with BE;controls will be two groups, subjects with reflux symptoms, and population controls. The data will be collated, and placed in a central repository. Multivariate logistic regression will be performed, and model variables will be estimated using maximum likelihood methods. Our expected results will define the relationship between three modifiable risk factors and Barrett's esophagus, and how they may be differentially expressed between women and men. The relevance of this project to the Institute is demonstrated by its responsiveness to NIDDK RFA, PA-06-151. This RFA promotes secondary analysis of data as an economical way of examining important research questions. Project Narrative Barrett's esophagus (BE) is a precancerous condition of the esophagus that is very common. Although about one quarter of people with BE are women, little work has been done to understand the risk factors for this condition among women and how they differ from risk factors among men. By studying three potential risk factors for BE in women (tobacco smoking, body size, and body fat distribution), we hope to better understand how this condition develops and why it behaves differently in women and men.